Radiological risk assessment of natural radionuclides in the whitemouth croaker (Micropogonias furnieri Desmarest, 1823) in Brazilian tropical seas

This study assesses the radiological risk to the whitemouth croaker (Micropogonias furnieri Desmarest, 1823) by calculating the dose to biota. Samples were collected, identified, and prepared for analysis from Sepetiba Bay, Rio de Janeiro, Brazil. The activity concentration (AC) results of ²³⁸U, ²³⁵U, ²³⁴U, ²³²Th, ²³⁰Th, ²²⁸Th, ²²⁸Ra, ²²⁶Ra, and ²¹⁰Pb are expressed in Bq·kg^-1. The study highlighted that biota radioprotection does not recommend dose limit concepts due to model boundary conditions, focusing instead on Derived Consideration Reference Levels (DCRL), which are used to screen for potential deleterious effects of ionizing radiation. The radionuclide-specific Dose Coefficient (DoCo) values for the analyzed radionuclides in saltwater fish are presented. The average dose rate found in M. furnieri was 7.72^-2 μGy∙d^-1. This average dose rate falls within the background range, suggesting no visible biological effects. The research emphasizes the need for radiological risk assessments in tropical regions, which are often underexplored compared to temperate regions. The study calls for broader studies using representative organisms to inform national legislation aimed at protecting biota from radiological risks, ensuring a comprehensive understanding of environmental safety and health.